Inheritance And Selection

Question 1

What’s monohybrid inheritance?

Answer 1

Inheritance of 1 gene

Question 2

What’s co-dominance?

Answer 2

Both alleles of a gene are expressed in the phenotype of the heterozygote.

Question 3

What’s sex linked inheritance?

Answer 3

Inheritance of alleles found on the x and Y chromosomes

Question 4

Why must all males with a recessive sex linked condition must have a mother who’s a carrier or has the conditions?

Answer 4

The X chromosome is inherited from the mother

Question 5

All females receive an X chromosome from their father, if he has a recessive sex linked condition, will they be a carrier?

Answer 5

Yes

Question 6

How many copies of an allele do male need to have a recessive sex linked condition?

Answer 6

Only 1, they only have 1 X chromosome

Question 7

When’s the only time a female will have a recessive sex linked condition?

Answer 7

When they’re homozygous recessive (2 recessive alleles)

Question 8

What are Dihybrid crosses with no linkage?

Answer 8

Inheritance of 2 different characteristics controlled by 2 differently genes found on 2 different chromosomes

Question 9

What happens in meiosis 1 which means genes on different chromosomes are inherited independently?

Answer 9

Homologous pairs segregated independently

Question 10

Define epistasis.

Answer 10

Allele of 1 epistatic gene masks the expression of a 2nd gene

Question 11

What does recessive epistasis mean?

Answer 11

Only a homozygous recessive genotype on the epistatic gene masks expression of a 2nd gene

Question 12

What does dominant epistasis mean?

Answer 12

Organisms genotype can be hetero or homozygous to show effect

Question 13

What’s linkage?

Answer 13

Inheritance of genes located on same autosomal chromosome

Question 14

What’s the formula for chi squared?

Answer 14

Question 15

How do you workout degrees of freedom?

Answer 15

No. Of categories if data - 1

Question 17

What does the Hardy-Weinberg principle do?

Answer 17

Estimates the frequency of alleles

Question 18

Define population.

Answer 18

Group of organisms of same species living in a particular place at a particular time with organisms being free to interbreed

Question 19

Define gene pool.

Answer 19

Complete range of genes in a population

Question 20

Define allele frequency.

Answer 20

How often an allele occurs (expressed as a %)

Question 21

Define genotype frequency.

Answer 21

How often a genotype occurs in a population expressed as a %

Question 22

When can the Hardy-Weinberg principle be used?

Answer 22

• large population
• mating = random
• one allele does not confer an advantage so no natural selection occurring
• no emigrants or immigrants
• no mutations occur

Question 23

What’s the equation predicting allele frequency?

Answer 23

p+q = 1

p= dominant allele
q = recessive allele
p^2 = homozygous dominant genotype
2pq = heterozygous genotype
q^2 = homozygous recessive genotype

Question 24

Whats the equation used to predict genotype frequency?

Answer 24

p^2 + 2pq + q^2 = 1

p= dominant allele
q = recessive allele
p^2 = homozygous dominant genotype
2pq = heterozygous genotype
q^2 = homozygous recessive genotype